Silicone putty retarder

ABSTRACT

A retarder roller for limiting the speed of a free running load on an inclined conveyor. The roller comprises a stator and a rotor rotatable mounted on the stator and forming a housing for the stator. The housing is filled with silicone putty. The stator and housing are provided with vanes for cutting through and displacing the putty as the housing is rotated.

This application is a continuation-in-part of my prior copendingapplication Ser. No. 351,061, filed Apr. 13, 1973, now abandoned, whichwas a continuation of my prior application Ser. No. 176,742, filed Aug.31, 1971, now abandoned, which is a continuation of my prior applicationSer. No. 850,835, filed Aug. 18, 1969, now abandoned.

This invention relates to a conveyor and more particularly to a brakingdevice for governing the speed of a free running load on an inclinedconveyor.

The conveyor of the type herein referred to comprises a pair of spacedparallel rails with each rail provided with at least one row of closelyspaced rollers. The rails are set at a pitch which is sufficient toallow gravity to move a load against the resistance of the rollers. Ifthe pitch is too great the control of the load is lost and the loadacquires a run away speed that could be disastrous. If the pitch is toosmall the load will not move under the influence of gravity. It istherefore an object of this invention to provide a conveyor which can beset at a pitch steep enough to insure movement of the load but isprovided with a retarding device to prevent the load from acquiring arun away speed.

It is a further object of this invention to provide a governing devicefor retarding the speed of a load on a gravity type conveyor.

It is a further object of this invention to provide a device asaforesaid which can be used as a roller in supporting the load on agravity type conveyor.

It is a further object of this invention to provide a device asaforesaid in which the resistance of the device is proportional to thespeed of the load.

It is a further object of this invention to provide a device asaforesaid which can be substituted for the rollers or other brakingdevices now used in gravity type conveyors.

It is a further object of this invention to produce a device asaforesaid in which the retarder is of the same size as existing rollersto permit easy substitution of the instant retarder for standard rollsin existing installations without redesign.

These and other objects of the invention will become manifest on readingthe following description in conjunction with the accompanying drawingwherein:

FIG. 1 is a perspective view of a gravity conveyor with the retarders inposition to engage a pallet;

FIG. 2 is a perspective view of a conveyor cart for use on an inclinedway with a pair of retarders for limiting the speed of the cart;

FIG. 3 is a view in section of the retarder;

FIG. 4 is an exploded view of the retarder of this invention;

FIG. 5 is a side view of the stator;

FIG. 6 is a view taken on the line 6--6 of FIG. 5, and

FIG. 7 is a side view of FIG. 6.

In accordance with the invention selected rollers of each rail of theconveyor are formed to provide a retarder for limiting the speed of theload. The retarders each comprise a stator, having vanes, secured to therail and a rotor secured around the stator to operate as a roller forthe load and a housing for the stator. The housing is filled with asemi-solid dilatent fluid such as silicone putty and is formed withinternal vanes to carry the putty in a circular orbit as the housing isrotated by the load.

The silicone putty, which can be SS-91, Silicone Bouncing Putty, aproduct of General Electric Company, will flow slowly when left inplace. When low pressures are applied thereto, the rate of flow is notproportional to the force. Thus, it acts as a non-newtonian thixotropicliquid wherein the rate of flow increases slightly with shearing stress.At higher pressures the putty acts as a plastic solid, since rate offlow is proportional to shearing stress above a certain yield value.When pressures are applied suddenly, the putty becomes dilatant, i.e.,the material becomes hard and brittle, and rate of flow increases lessthan proportionally with pressure. The vanes on the stator react againstthe putty and, through the putty and internal vanes, against the housingto limit the speed of rotation of the housing. It is a property ofsilicone putty that its resistance to deformation increases as thedeforming force increases. When used in a conveyor, the putty willdeform to permit the load to move within a selected speed limit but willstrongly resist the movement of the load above this limit.

In another form of this invention a wheeled cart is supplied with atleast one retarding roller of this invention.

With reference to the drawing there is disclosed a gravity type conveyorcomprising a pair of spaced rails 2 and 4 supported at a preselectedpitch by pedestals 6 and 8. Each rail comprises a pair of channelmembers 10 and 12 having rotatably mounted therebetween series ofrollers 14 for transporting a load L. The pedestals comprise braces 16,18 to which the rails are secured. Legs 20 and 22 of selected lengthsupport the braces and provide the selected pitch.

Selected rollers R of the series of rollers 14 are the speed controllingrollers of this invention. Each roller comprises a stator having a hub24 provided with a D-shaped opening 26 and vanes 28 integral therewithand connected to the hub by a flange 30 having a reduced section 32. Arotor, comprising a pair of members 34 and 36 adhered together, isrotatably mounted on the stator by needle bearings 38 and 40. The innersurfaces of the members 34 and 36 are formed with vanes 42, 44, and 46for a purpose to be described below.

The vanes 28 are shaped as rhomboids having the edges 48 and 50 formedat the acute angles. The alternate vanes are tipped in the samedirection with the consecutive vanes tipped in opposite directions abouta common plate P--P.

The stator member is formed with beveled surfaces 52 for engagement bysharp edged flexible lips 54. When assembled the lips are pressedagainst the surfaces 52 to form a seal to prevent the escape of theputty which fills the chamber 55.

The rollers are assembled between the channel members 10 and 12 andsecured thereto by a locking pin 56 having a cross section congruent tothe D shaped opening 26 and having an arm section 58 that is longer thanthe shortest distance between the opening and the undersurface 60 ofchannel member 12 to lock the pin against rotation. In the completedassembly the outside diameter of tire 62 of rollers R is slightlygreater than the outside diameter of the other rollers to assure goodcontact with the load which is usually in the form of a loaded pallethaving uneven roller engaging surfaces.

In operation, the moving load rotates the rotor. The internal vanes 42,44, 46 urge the putty to rotate with the rotor and the rotating putty iscarried past the fixed vanes 28 where either of the sharp edges 48 or 50(depending on the direction of rotation of the putty) cut into the puttyand force the putty to flow against the flat surfaces 51 of the vanes.The speed of the putty, as it is sliced and thrust by the fixed vanes,determines the resistance of the rotor to the rotating force produced bythe load. This resistance determines the maximum speed attained by theload. The alternate tilting of vanes 28 prevents the successive cuttingedges from slicing through the putty before the putty has flowed to healthe previous cutting. However, a lower maximum speed of the rotor couldallow the putty to reform and heal and would permit successive cuttingedges to be positioned in the same plane.

It is preferred to make the stator and rotor of synthetic plasticmaterial such as nylon but metal could be used. The tire 62 is formed ofan elastomeric material to provide sufficient friction to provideagainst undue slippage when suddenly engaged by the moving load.

In FIG. 2 is disclosed a cart comprising a platform 64 carried by wheels66. The wheels are rotatable on axle 68 supported in brackets 70 securedto the platform. Retarder rollers R are mounted on the axle. In use, thecart is rolled down an inclined trackway and is limited in speed by theretarding force of the rollers as set forth above.

While I have disclosed silicone putty as the deformable material othermaterials having the consistency and above noted properties of siliconeputty, gelatinous substances, or grease, and which are classified assemisolid materials can be used.

Though the invention has been described with respect to specificpreferred embodiments thereof, many variations and modifications willimmediately become apparent to those skilled in the art. It is thereforethe intention that the appended claims be interpreted as broadly aspossible in view of the prior art to include all such variations andmodifications.

What is claimed is:
 1. A retarder roller comprising a stator, a rotorsurrounding the stator and forming an enclosed housing having walls,silicone putty in the housing, and means on the rotor and stator fordeforming the material, wherein the deforming means comprises vanes onthe stator and means on all the walls of the housing for holding theputty for rotation therewith, the vanes on the stator comprising membersextending radially into the putty, each having a wedge shaped portionpresenting a sharp edge opposite to the direction of rotation of therotor and putty, the edges on consecutive vanes being on opposite sidesof a common plane normal to the rotor axis.
 2. A retarder rolleraccording to claim 1 wherein an elastomeric tire is mounted on therotor.
 3. A retarder roller comprising a stator, a rotor surrounding thestator and forming an enclosed housing having walls, silicone putty inthe housing, and means on the rotor and stator for deforming thematerial, wherein the deforming means comprises vanes on the stator andmeans on all the walls of the housing for holding the putty for rotationtherewith, the vanes on the stator comprising members extending radiallyinto the putty, each having a wedge shaped portion presenting a sharpedge opposite to the direction of rotation of the rotor and putty, thevanes being rhomboids with the acute angles extending circumferentially,the edges defined by the acute angles on consecutive vanes being onopposite sides of a common plane normal to the rotor axis.
 4. A retarderroller as defined in claim 3 further including a tire of elastomericmaterial mounted on the rotor.
 5. A retarder roller comprising,acylindrical housing member closed at its ends, an inner axiallyextending member within the housing member having end portions extendingthrough the ends of the housing to permit relative rotation of themembers, a semi-solid material within the housing member having dilatantfluid flow characteristics, the inner surface of the housing memberbeing provided with means for engaging and retaining the materialagainst rotational movement relative thereto, and angularly spacedblades on the inner member within the housing projecting substantiallyradially with respect thereto into the material, said blades eachincluding a wall surface with a sharp forward edge substantially facingthe path of rotation of the members for slicing through the materialduring relative rotation of the members, the edges of adjacent bladeslying on opposite sides of a plane normal to the axis of rotation, saidwall surfaces of adjacent blades being angularly related to each otherwith their rear portions closer than their forward edge portions so asto return the material deflected laterally by the previous adjacentblade during relative rotation of the members.
 6. A retarder rolleraccording to claim 5 including an elastomeric tire mounted on an outersurface of one of the members.
 7. A retarder roller comprising a stator,a rotor surrounding the stator and forming an enclosed housing having awall, a semisolid material having dilatant fluid flow characteristics inthe housing, and means on the rotor and stator for deforming thematerial, wherein the deforming means comprises vanes on the stator andmeans on all the walls of the housing for holding the material forrotation therewith, the vanes on the stator comprising members extendingradially into the material, each having a wedge shaped portionpresenting a sharp edge opposite to the direction of rotation of therotor and material, the edges on consecutive vanes being on oppositesides of a common plane normal to the rotor axis.
 8. A retarder rolleraccording to claim 7 including an elastomeric tire mounted on an outersurface of one of the members.
 9. A retarder roller comprising:acylindrical housing member closed at its ends, an inner axiallyextending member within the housing member having end portions extendingthrough the ends of the housing to permit relative rotation of themembers, a semi-solid material within the housing member having dilatantfluid flow characteristics, the inner surface of the housing memberbeing provided with means for engaging and retaining the materialagainst rotational movement relative thereto, and angularly spacedblades on the inner member within the housing projecting substantiallyradially with respect thereto into the material, said blades eachcomprising an element providing a wedge-shaped portion with a sharp edgethereof facing the path of rotation of the members for slicing throughthe material during relative rotation of the members, and said sharpedges on consecutive blades being on opposite sides of a common planenormal to said axis.
 10. A retarder roller according to claim 9including an elastomeric tire mounted on an outer surface of one of themembers.
 11. A retarder roller comprising:a cylindrical housing memberclosed at its ends, an inner axially extending member within the housingmember having end portions extending through the ends of the housing topermit relative rotation of the members, a semi-solid material withinthe housing member having dilatant fluid flow characteristics, the innersurface of the housing member being provided with means for engaging andretaining the material against rotational movement relative thereto, andangularly spaced blades on the inner member within the housingprojecting substantially radially with respect thereto into thematerial, said blades each comprising an element providing awedge-shaped portion with a sharp edge thereof facing the path ofrotation of the members for slicing through the material during relativerotation of the members, and said elements being of rhomboidal shape.12. A retarder roller according to claim 11 wherein said sharp edges onconsecutive vanes are on opposite sides of a common plane normal to saidaxis.
 13. A retarder roller according to claim 12 including anelastomeric tire mounted on an outer surface of one of the members. 14.A retarder roller according to claim 11 including an elastomeric tiremounted on an outer surface of one of the members.